This invention relates to systems and methods for producing synthesis gas. More particularly, this invention relates to systems and methods for producing synthesis gas using fluidized bed reactors without an Air Separation Unit (ASU).
Currently complex industrial plants are built around the globe to produce synthesis gases for use in a variety of applications including conversion of natural gas to useful liquid fuels in a Gas-To-Liquids (GTL) plant, generation of hydrogen gases and other processes. The ASU is typically an integral part of a GTL plant and costs about one third of the capital cost of a GTL plant. Therefore one challenge faced by these complex industrial plants is how to eliminate or reduce the capital expenditure that is required to build ASU in those plants.
Liquid hydrocarbons for fueling different types of engines can be synthesized in Gas-to-Liquid (GTL) plants in which synthesis gas (a mixture of CO and H2) is catalytically converted to liquid fuels. For utilization in such plants, synthesis gas is produced either by homogeneous Partial Oxidation (POX) or by catalytic partial oxidation (CPO) of natural gas (NG) or other hydrocarbons. In the CPO process the hydrocarbons react with oxygen (O2) gas that is separated from air. Cryogenic technology or multiple stage pressure swing adsorption units are typically used to separate O2 from air. The air-separation unit used in today's plants is quite expensive. In addition, the cryogenic process of generating pure O2 from air at the required pressure is energy intensive. The cost of capital and operation of the air separation unit is substantial.
Accordingly, there is a need for a process to produce synthesis gas economically wherein the requirement of the expensive air separation unit is eliminated.